Develop instrumentation for the noninvasive detection, characterization, and quantification of atherosclerosis in the early stages of the disease in a non-human primate model. Early stages of atherosclerosis is defined here as the stage where the arterial wall thickens and becomes stiffer. Sufficient resolution will be attempted by signal processing techniques and development of a high resolution transducer pulse. The animal colony will consist of 18 adult male M. fascicularis monkeys consisting of three groups. The first group is a control group, the second group is fed a diet high in cholesterol, and the third group is fed a diet high in peanut oil. After sacrifice, correlations between ultrasound findings and histology will be made.